2007 NBS Sierra Denali Codes P2715 and P0700, occasionally revs high

BruceW · July 13, 2013

My truck has 123K miles on it. The transmission is a 6 speed 6L80. About a month ago I was towing a 23' 8'6" beam, 5000 pound ski boat about 300 miles. The transmission temp maxed out around 193. About 100 miles before our destination the check engine light came on. It was late and we were going through small towns so I did not have a chance to check the code. I was in tow haul mode and never noticed any issue. The next day the CEL was gone.

Yesterday I was driving around unloaded and had the truck fail to shift and rev up to 3K+ rpm. At that time I noticed that the CEL was back. I was half a mile from home. I do not believe that it shifted on the way home, it seemed to be locked in gear.

Once home I stopped and restarted the engine. After restarting the CEL remained but the transmission seemed to function normally. Later I drove 15 miles into town to have the code read. The codes were P2715 and P0700. I did not ask to have the codes cleared.

I have had an issue with the 1st to 2nd or 2nd to 3rd shift where it seems to be a delayed shift with some revving between for years. This seems to happen when I am not accelerating hard or loaded.

Today I drove about a 25 mile loop to talk to a transmission guy I know and take the kids for a snack. On the way I shifted manually up and down through the gears. It shifted smoothly. On a short divided highway section I floored it to accelerate. It downshifted twice. The first was smooth and good. It seemed to have some free revving with the second, although I may just be overly critical about this.

The transmission fluid was changed approximately 10K to 15K miles ago.

I am hoping that others can share their experience with and solutions for similar issues with this transmission. What do you guys suggest?

Thanks in advance.

Edited July 13, 2013 by BruceW

Jennabear · July 13, 2013

Off the top of my head, the p0700 is a TCM code, meaning there is something wrong with the TCM. Sounds like something you may need to go to the dealer for.

Sent from a jelly bean.

desrtrat · July 13, 2013

here is a list of codes..can be down loaded or printed. should help you some, and anyone else who can use the info..

http://www.scribd.com/doc/96676274/OBD2-Trouble-Codes

good luck

gmtech4 · July 14, 2013

700 is sent from the trans control module(TCM) to the ECM that there is a code in the TCM ,,,,,you have to now scan the TCM for the real code

the other code is engine ,

the first thing to do is clear all codes in both modules and drive the truck to verify a hard fault and then re scan and then have the code printed out and follow the diag tree

or

take it in

Edited July 14, 2013 by govtech4

BruceW · July 14, 2013

P0700 is a request from the transmission to turn on the CEL.

P2715 is Pressure Control Solenoid "D" (4) Stuck On.

I talked with a mechanic today. He said that it sounded like something had broken loose after the fluid change and must have gotten into solenoid 4 or the associated valve.

I went out for a drive today and found that the CEL had cleared itself. He said they will do that after X successful trips without the problem reoccurring.

I decided to test it a little to see how the transmission was performing. I started off with a leisurely drive for about 10 miles of twisty and hilly road. It performed fine so I found an abandoned stretch of road and did about 20, 0 to 80 runs. I got the transmission temp up to 205 which is higher than I have ever seen trailering. It did not miss a shift. I often used manual shifting and tow haul mode.

What do you guys thing? Should I pursue this further?